The mechanism and effects of localized corrosion in dental amalgam restorations is being studied in vitro. The tests include measurements of electrode potentials and currents in occluded corrosion cells, determination of the solution chemistry within specimens and samples of the individual phases of dental amalgam microstructure. Tensile and compressive strength of dental amalgam is being determined as a function of the corrosion exposure, and the microstructure and fracture surfaces are examined to determine the extent of the corrosion damage. Both conventional and high-copper amalgam will be examined.